"add new comment" link displayed when it shouldn't be

Summary: Anonymous user can see a link to add a new comment when it is impossible for them to do so.

Background: Fresh Drupal 4.7.5 install, to host a simple family blog. Only Content Type in use is "blog entry". Should allow anonymous users to post and view comments.

To repeat:
- At Administer >> Access Control >> Permissions, enable "post comments without approval" for "anonymous user" role. Click "Save Permissions".
- Return to home page amd log out.
- On homepage, no entries show "add new comment" link, but if you then opena blog entry to read it, you'll see the "add new comment" link at the bottom of the page. However if you click the link, you get the error message "You are not authorized to view comments."

Suggestions:
- Since there is no point to enable "post comments without approval" without also enabling "access comments" (teh user will just get the "you are not authorized..." error), it would also be good to change the access control page to display some error if that combination is attempted. Or is it possible to grey out the "post comments without approval" option if "access comments" has not been enabled?
- Then also make the display of the "add new comment" link consistent wherever the node is displayed. Either display it on both home page and when the node is opened, or neither.